Effects of lead and socio-cultural factors on cognition and behaviour of children in Port Pirie and Broken Hill

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The effect of lead on children's 'intelligence' is controversial. Poorer IQ scores in children with higher exposure to lead, have been found reasonably consistently, - but there is disagreement on whether lead exposure is simply a common ASSOCIATE of poor IQ, or whether it actually CAUSES deficits. In 1994, the NHMRC prudently recommended a graded series of interventions to be implemented, depending on the proprtion of children in the community with blood lead concentrations in specific categories above 10 ug lead -100 ml of blood. The choice of this figure (10 ug-dl) was more pragmatic than scientific; there being very little data on the health effects of exposures below 10 ug-dl available at that time. A recent analysis of pooled data from past studies has now suggested there may be very large effects on child IQ at blood lead concentration BELOW 10 ug-dl. Health authorities will soon be lobbied intensely to spend vast sums on new lead abatement programs. Cities like Port Pirie and Broken Hill (where cooperative programs have achieved such significant reductions in lead exposure that a high percentage of their children now have blood lead levels below 10 ug-dl), will be forced to examine expensive options to avoid closure of the industries which provide their economic backbones, if this analysis proves to be correct. Our proposal argues that before committing to new and costly abatement programs, there is an urgent need to augment our evidence-base by conducting a new study ofchildren with lead exposures below 10 ug-dl, using more modern measures of intelligence. The study will pay closer attention to some of the socio-cultural and inherited determinants of child IQ which may have confounded the lead-IQ association in past studies, and will supplement IQ assessments (which are now considered to derive from a very old and narrow view of intelligence) with new tools for measuring 'intelligence' that may be less socio-culturally dependent.